Post on 05-Jan-2016
description
The VLT-FLAMES Survey of Massive StarsChris Evans (ING, La Palma)Tartu August 2005
Main collaboratorsSteve Smartt, Philip Dufton, Ian Hunter (Belfast)
Danny Lennon (ING)
Carrie Trundle, Artemio Herrero (IAC)
Alex de Koter, Rohied Mokiem (Amsterdam)
Mike Irwin (Cambridge)
FLAMES survey of massive starsESO Large Programme (PI: S. Smartt)
112hrs on the VLT with FLAMES
FLAMES has 137 fibres which feed the Giraffe spectrograph
Target fieldsFields chosen to sample a range of Z and ages:
Some of our motivationsObtain CNO abundances for a large, homogenous OB sample
Determine vsini distributions, evidence for Z-dependence?
Armed with vsini, explore CNO cf. evolutionary models
Tests of the Z-dependence of O star mass-loss rates
Un-planned, but interesting: Binary detection!
Target fieldsFields chosen to sample a range of Z and ages:
Target fieldsFields chosen to sample a range of Z and ages:Evans et al. (2005)
Target fieldsFields chosen to sample a range of Z and ages:
Observational informationHigh resolution: R~20,000
800 stars observed over the 7 fields:@ 6 -settings, coverage from 3850-4750, 6400-6650 LMC/SMC fields observed 6 times at each -setting
Obtained in service mode, often different observational epochsfor each -settingfor repeat observations at each -setting
Observational informationHigh resolution: R~20,000
800 stars observed over the 7 fields:@ 6 -settings, coverage from 3850-4750, 6400-6650 LMC/SMC fields observed 6 times at each -setting
Obtained in service mode, often different observational epochs:for each -settingfor repeat observations at each -settingO9.5 VV = 15.29
Targets in NGC 346V-band DSS
Targets in NGC 346ACS (HST/Nota)V-band DSS
Targets in N11NIR (from R. Barba)V-band DSS
Targets in N11NIR (from R. Barba)V-band DSSLH 10LH 9
Census of young MC clusters
Census of young MC clusters
Incidence of Be-stars: there is a selection effects for the Be-stars, one cannot simply take the above numbers at face value!
Be-type spectra in NGC346
H
Census of young MC clusters
62 O-type stars, ~half of them previously unknown
Analysis now underway in Amsterdam [more in Alex de Koters talk later today]
New O2-type star
New O2-type starO2-2.5 III(f*)
Still small number statistics at earlier than O3 (~10 stars)
N11 field
N11 field
N11 field
N11 fieldO2 star
Binary detectionService observations @ multiple epochs checks for binarity
Single/double-lined binaries found from simple methods:from visual inspection when classifying the spectrafrom radial velocity measurements of the H, He & Si lines [accurate to ~10 km/s]
More sophisticated methods now being used to cross-correlate the individual spectra at each -setting [accurate to ~5 km/s, which will no doubt find further binaries]
Binaries in the young MC clusters
Binaries in the young MC clustersNote that these numbers do not include those found from cross-correlation methods expect them to go up slightly
Binaries in the young MC clustersNote that these numbers do not include those found from cross-correlation methods expect them to go up slightly26%37%
Binaries in the young MC clustersNote that these numbers do not include those found from cross-correlation methods expect them to go up slightly29%36%
Binary detection: time samplingNGC 346N1157 days84 daysJulian Date
Binaries in the young MC clustersFirm lower limits on binary fraction, to then compare with different star formation scenarios (eg Bally & Zinnecker, 2005) 29%36%
N abundances in B stars in NGC 346Provisional results from TLUSTY analysis, (Ian Hunter, Belfast)
N abundances in B stars in NGC 346Provisional results from TLUSTY analysis, (Ian Hunter, Belfast)Binaries
SummaryLots of interesting objects in these young clusters!
Overview paper of LMC/SMC data, binary detection, radial velocities, etc: Evans et al., in prep.
Parallel studies:LMC/SMC O-star analysis: AmsterdamGalactic vsini paper: BelfastAnalysis of narrow-lined stars: Ian Hunter (Belfast)Analysis of O stars in NGC 6611: Herrero/Villamariz (IAC)